Mute renderer output when calling through script
That is normal output for rendering from the cli and blender doesn't offer an option to reduce it. The way to mute it is to redirect the output for the shell, the method varies depending on the shell used. While redirection is normally used to save output to a file you can use /dev/null as a file to effectively scrap it as it is output.

For sh or bash (I believe also works in windows terminal) -

blender --background --python myscript.py &gt; /dev/null 2&gt;&amp;1


for csh

blender --background --python myscript.py &gt;&amp; /dev/null


The above examples redirect both STDOUT and STDERR to /dev/null, to get more control you can direct only STDOUT to /dev/null (by only adding &gt; /dev/null) which will consume blenders render progress and then print your output to STDERR, which your script can do with print(myoutput, file=sys.stderr)

Another approach is to use a script instead of calling blender directly, this will allow you to catch all of blenders output and only send your info to the terminal. By adding a unique tag you can separate your output from blenders progress report.

from subprocess import check_output

render_progress = check_output(['blender','--background','--python','myscript.py'])

msg = render_progress.split('*#*#*#')[1]

print(msg)


A similar result could also be achieved with a shell script.